Yes, it does run in families. All 3 of my children are on long term Zithromax. This is what I would do if I were pregnant. I am not a doctor. But I am pretty experienced in kids with auto-immune disorders, so here goes.
1. Eat organic food as much as possible and avoid sugar as much as possible
2. Take lots of fish oil and your pre-natals of course
3. Don't use chemicals while you are pregnant, and for cleaning the house use white vinegar
4. Make sure your hand soaps are fragrance free
5. When your little one is born, breast feed if you can while staying organic, and if not, use Pregestimal
6. If possible be dairy free a couple of weeks before you give birth and then for the first year you are breastfeeding
7. Lot's of smoothies with greens in them!!
8. Keep up the "clean" living and do slow or no vaccines (check with your dr about this) and your little one should have a good chance of avoiding it.
Good luck. I know how hard it is to have children with auto-immune issues. But all 3 of mine are doing fantastic right now. I think that "clean" living definitely helps and you get used to it pretty quickly.